Method and apparatus for mechanical aeration of stacks of cardboard, paper or other sheet material



Dec. 31, 1968 G. RuuD 3,418,725

METHOD AND APPARATUS FOR MECHANICAL AERATION OF STACKS OF CARDBOARD, PAPER OR OTHER SHEET MATERIAL Filed May 26, 1967 Sheet I of 2 INVENTOR.

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METHOD AND APPARATUS FOR MECHANICAL AERATION OF STACKS 0F CARDBOARD, PAPER OR OTHER SHEET MATERIAL Filed May 26, 1967 Sheet 2 of 2 United States Patent 9 Claims. (or. 34-33 ABSTRACT OF THE DISCLOSURE The invention is related to mechanical means for airing stacks of newly printed sheet material to prevent sticking and smearing of the printed text. The apparatus comprises a base for supporting the stack with the sheets positioned vertically and a sheet-lifting means having a ridge is moved under the stack in order to move the sheets in relation to each other. The sheets may also be vibrated.

When sheets of cardboard, paper or similar sheet material have been printed on in a printing machine and subsequently stacked, the sheets adhere to one another 5 during the drying period. This may cause the print to off set onto adjacent upper and lower sheets and thereby damage the product. In order to prevent this off setting, the sheets must be loosened from one another at the right time. In technical terms this is called aeration of the stack and is undertaken manually. The aeration is usually carried out by removing a pile of sheets from the top of the stack and subjecting the sheets to a bending or similar movement so that the sheets slide away from one another and adhesion is prevented. It is of great importance to the further mechanical production in sheet feeding machines that the sheets do not adhere together. The actual operation of loosening the sheets from one another must, as already mentioned, be undertaken at the right time, that is to say that the sheets must not be allowed to remain stacked for too long a period of time after printing, and consequently the aeration is frequently carried out before or after usual working hours. This manual operation is exhausting, time consuming and expensive, and it is the object of the present invention to simplify this operation by loosening the sheets from one another mechanically.

The method comprises disposing the stack on an approximately horizontal base, in such a manner that the plane of the sheets is in approximately vertical position, and the stack is thus supported with the sheets endwise such that it is capable of expanding somewhat in longitudinal direction during the operation. The lower edges of the sheets which rest upon the base are then acted on by one or more sheet lifting members which, during movement along the stack, raise the sheets in relation to one another so that there occurs a displacement among the sheets which prevents adhesion.

The lifting apparatus may be constructed in many ways; it may for instance be in the form of a ruler the cross section of which in both lateral directions inclines upwardly toward a thicker central portion. If such a ruler is mounted parallel to, and in contact with, the lower adges of the sheets, and guided on a fixed base in a direction transverse of the lower edges of the sheets, the sheets will be raised by the leading edge of the ruler successively above the thick portion of the ruler and slide downwardly again toward the base when the downwardly inclined rear trailing edge of the ruler has passed. Such a lifting member may have a reciprocal movement, or a plurality of such rulers may, for instance, be mounted on an endless belt which runs over rollers mounted in 3,418,725 Patented Dec. 31, 1968 the base. In order to protect the lower edges of the sheets as much as possible, a thin flexible band of metal or other suitable material may be disposed between the sheet lifting member and the sheets, upon which band the sheets rest. When the ruler is moved beneath this band the weight of the sheets will press said band against the ruler so as to raise and lower the sheets in accordance with the contour of the ruler.

The cross sectional form of the sheet lifting member may be varied, and an advantageous solution is to form the top portion of the ruler as a roller which greatly reduces the friction against the band when rolled against the underside thereof.

In order to improve even further the effect achieved by raising the sheets, the base, or portions of the base, upon which the sheets rest or are supported, or even the actual lifting member, may be subjected to vibration.

A further advantageous effect may be achieved by subjecting the sheets in the stack to compressed air which is directed to one or more of the edges of the sheets to force air in between said sheets.

The invention is more completely described in the following with reference to the drawing where FIG. 1 is an elevational view showing an embodiment of the apparatus with the stack of sheets in position on the base.

FIG. 2 shows the same in partial section along the line IIII in FIG. 1.

FIG. 3 shows the lifting member with the vibrator and conveyor, in partial section along the line III-III in FIG. 4.

FIG. 4 shows the same in partial section along the line 1VIV in FIG. 3.

FIGS. 1 and 2 show the most important members of the apparatus in the preferred embodiment example disposed upon a base 19 and comprising a framework 1 having a rigid end plate 12 and side Plates (not shown) for guiding the sheets of the stack 11, and also a movable end piece 13, together with the members, mounted in and on the frame, such as a reciprocally moving bogie 4 which carries the sheet lifting members 3 with its vibrator means 5, 6, 7 and 23, further, guide rods 9 and a motion screw 8 with motor 20, together with the flexible band or web 10 and the base plates 2 thereof, supported in the frame by the angle irons 22. The apparatus is mounted pivotally on the base 19 about bolts 18 and, by means of a pressure cylinder 16 and connection 17, may be pivoted from horizontal to vertical position, as indicated by broken lines to the right in FIG. 1. In said vertical position of the apparatus, the sheet stack 11, arriving from the printing machine after the necessary waiting time, are driven on a platform or the like 15 and disposed upon the end plate 12 of the apparatus and the movable end piece 13 is lowered onto the top of the stack. The sheet lifting member or the cross bar 3 being disposed previously in its end position in the left hand end portion of the frame in accordance with the drawing. The stack 11 is then pivoted to the horizontal position shown in FIG. 1, and the end piece 13, is adjusted with sufficient clearage between said end piece and the stack so as to allow the stack the necessary freedom of movement.

FIGS. 3 and 4 show in greater dimension the barshaped lifting member 3 which is mounted on two spring loaded bolts 5, which are mounted vertically movable in a bogie or slide 4, which glides on guide rods 9 and is moved reciprocally by means of a motor driven screw 8. On the trolley, bogie or slide 4, a motor 7 is further mounted, said motor driving a shaft 23 which, by means of eccentrics 6 imparts a rapid upward and downward movement to the spring loaded bolts 5, at the respected ends of the shaft 23, which causes vibration of the lifting member 3. In FIG. 4 the sheet-lifting member 3 is illustrated as being provided with leading and trailing edges 3' which incline upwardly to the ridge as shown. These edges, of course, alternately become leading and trailing, depending upon the direction of movement of the sheetlifting member 3.

When the sheets are of greater width, it is expedient to divide the flexible band into two or more narrower bands, and the bar shaped sheet lifting member 3 may also be divided into several parts. This also applies to the base plate 2. The end piece 13 is shown with a pivotable end plate 14, the purpose of which is to permit the removal of one or more sheets, as necessary, during the operation.

A means 21 with a nozzle for the supply of compressed air is shown mounted above the stack at the location where the sheets are raised by the lifting member, and this apparatus is connected with the bogie 4, in a manner not shown, so that it accompanies the movement of the bogie and is at all times directly above the lifting member. The object of this apparatus is to facilitate the seperation of the top portions of the sheets, and particularly aids the lowering of the sheets after the top portion of the lifting member has passed beneath them.

Having described my invention, I claim:

1. Method of aeration of a stack of printed sheets to prevent them from sticking together, comprising positioning the stack on a support with the sheets substantially vertical and with their lower edges resting on the support, and successively acting on the lower edges of the sheets of the stack in a direction transverse thereto to successively raise the sheets, thus raising and lowering the sheets of the stack successively in relation to each other.

2. Method of aeration of a stack of printed sheets to prevent them from sticking together, comprising positioning the stack on a support with the sheets substantially vertical and with their lower edges resting on the support, successively acting on the lower edges of the sheets of the stack in a direction transverse thereto to successively raise the sheets, thus raising and lowering the sheets of the stack successively in relation to each other, and vibrating the raised sheets of the stack on the support.

3. Apparatus for aeration of a stack of printed sheets to prevent them from sticking together, comprising means for supporting the stack with said sheets in vertical position, sheet-lifting means having a raised portion adapted to act on the lower edges of the sheets in succession and raise the sheets acted on when the sheet-lifting means is moved transversely under same.

4. Apparatus for aeration of a stack of printed sheets to prevent them from sticking together, comprising means for supporting the stack with said sheets in vertical position, sheet-lifting means having a raised portion adapted to act on the lower edges of the sheets in succession when moved transversely under same, said raised portions being constituted by a power operated bar extending parallel to said lower edges.

5. Apparatus for aeration of a stack of printed sheets to prevent them from sticking together, comprising means for supporting the stack with said sheets in vertical position, sheet-lifting means having a reciprocable raised portion adapted to act on the lower edges of the sheets in succession when reciprocated transversely under same, said raised portion being constituted by a bar extending parallel to said lower edges, said bar having inclining leading and trailing edges.

6. Apparatus for aeration of a stack of printed sheets to prevent them from sticking together, comprising means for supporting the stack with said sheets in vertical position, sheet-lifting means having a raised portion adapted to act on the lower edges of the sheets in succession and raise the sheets when the lifting means is moved transversely under same, and a band extending loosely over said raised portion of the sheet-lifting means and conforming to the same.

7. Apparatus for aeration of a stack of printed sheets to prevent them from sticking together, comprising means for supporting the stack with said sheets in vertical position, sheet-lifting means having a raised portion adapted to act on the lower edges of the sheets in succession when moved transversely under same, a band extending loose-1y over said raised portion of the sheet-lifting means and conforming to the same, and means for vibrating the sheet-lifting means. v

8. Apparatus for aeration of a stack of printed sheets to prevent them from sticking together, comprising means for supporting the stack with said sheets in vertical position, sheet-lifting means having a raised portion adapted to act on the lower edges of the sheets in succession and raise the sheets when said lifting means is moved transversely under same, the support being provided with a band extending loosely over said raised portion and conforming to same, said raised portion being connected to vibratory means, and means for directing air jets towards the raised portion of the stack of sheets.

9. Apparatus for aeration of a stack of printed sheets to prevent them from sticking together, comprising means for supporting the stack with said sheets in vertical position, sheet-lifting means having a raised portion adapted to act on the lower edges of the sheets in succession and raise the sheets when moved transversely under same, said raised portion being constituted by a bar extending parallel to said lower edges, said bar having inclined leading and trailing edges, and means for directing air jets towards the raised portion of the stack of sheets.

References Cited UNITED STATES PATENTS 3/1914 Gullberg et al. 27189 3/1966 Gebert 27189 XR U.S. Cl. X.R. 

